1. Field Of The Invention
The present invention is concerned with remote dispensers for base units containing a pressurized fluid, and to assemblies comprising remote dispensers connected to such base units by a flexible supply tube. Such devices find use in industrial applications for a variety of cleaning or other uses involving the delivery to a workpiece of a controlled spray of a substance, such as a solvent, cleaner or antistatic substance, from a pressurized container base unit, such as a conventional aerosol spray can.
It is often convenient or necessary, because of space limitations and to reduce operator fatigue, to utilize a remote dispenser attached to a pressurized base unit when it is desired to deliver a spray of a substance, for example, a solvent liquid for removing solder from and otherwise cleaning defective circuit boards to permit re-use of the boards in a manufacturing process. Other typical uses of such remote dispensers are for cleaning internal components of optical devices (cameras, projectors, telescopes, etc.) and electronics equipment (tape recording heads, etc.), and for cleaning or lubricating internal gears, electric motors and controls and the like. In such cases the manipulation of a conventional pressurized container containing a pound (0.45 kg) or more of solvent, cleaning agent or other material is often awkward or impossible in tight quarters. The remote dispenser has a trigger or other manual control to dispense the pressurized fluid. In addition, an "off" and "on" control on the base unit container is desirable in order to provide a shut-off means at the source of supply when the assembly is not in use.
2. Description Of The Related Art
Stephenson et al U.S. Pat. No. 3,650,438 shows a pressurized container assembly having a remote manually-operated nozzle wand dispenser connected by flexible tubing to an aerosol container base unit. The output supply of the base unit is controlled by a twistable container cap means mounted on it, the cap means permitting manual opening and closing of the spray nozzle of the base unit. Stephenson et al U.S. Pat. Nos. 4,278,188 and 4,350,299 each disclose an assembly consisting of an aerosol can connected by flexible tubing to a wand-like remote delivery nozzle which is equipped with a brush at the end thereof.
The flexible tubing used to provide a supply tube connecting the base unit to the remote dispenser may be connected to the aerosol can by being secured to a cap assembly which is specifically designed to accommodate it. However, such custom design increases manufacturing costs. On the other hand, the supply tube end may be simply inserted into the discharge bore of a conventional or off-the-shelf spray nozzle on the base unit. For reasons of economy it is desirable to use off-the-shelf stock plastic tubing and stock aerosol spray can nozzles; however, manufacturing tolerances for such stock items are such that the inserted tubing may readily be accidentally disengaged from the discharge bore of the base unit during movement of the remote dispenser by the operator, especially if the remote dispenser (which may be fitted with a brush) is used with a scrubbing motion. The nozzle on the base unit aerosol spray container must be locked in the open or discharge position in order to provide a steady supply of fluid to the remote dispenser. Accordingly, accidental disengagement of the supply tubing from the discharge bore of the nozzle of the aerosol spray container base unit results in a wasteful and possibly hazardous continuous discharge from the base unit until its nozzle can be closed or the delivery tube reinserted.
Clapp U.S. Pat. No. 4,682,713, assigned to the assignee of this application, addresses this problem by providing a locking means secured to the supply tube. The locking means is inserted into a seat on the base unit and serves to retain the fluid release valve in the open position, in order to continuously supply pressurized fluid to the remote dispenser. The locking means is designed so that inadvertently or deliberately pulling the supply tube from the base unit discharge bore also pulls the locking means from its seat, thereby releasing the fluid release valve to return to its normal, closed position and shut off the discharge of pressurized fluid from the disconnected base unit. The locking means of the '713 Clapp Patent may comprise a flexible rod (50 in FIGS. 1, 2, 3 and 4 of the '713 Patent) or a wedge-like member (72 in FIGS. 6, 7 and 8 of the '713 Patent). The structure of the '713 Patent is useful for the intended purpose. However, to attain reliable performance it is necessary to carefully control the length and flexibility of the rod 50 of the FIGS. 1-4 embodiment; otherwise, a sharp upward pull on the supply tube (16/68 in FIG. 1 of the '713 Patent) might pivot the tube upwardly and disengage it from discharge bore 36 without fully withdrawing locking means 50 from the aligned apertures of sidewalls 40, 40a. In such case, the release means would remain open and discharge fluid from the disconnected base unit. With respect to the wedge-shaped locking means 72 of the FIGS. 6-8 embodiment of the '713 Patent, it requires the provision of tabs (70 in FIGS. 6-8) or other custom structures on the release means in order to retain the locking means in place. While both illustrated embodiments of the '713 Patent are functional, the strength of the securement of the locking means (50 or 72) to the release means (20 or 20") is limited, especially if the fit of supply end 16a of tube 16 into discharge bore 36 is a loose one. Inadvertent disconnections of the supply tube, even if infrequent, result in annoyance and interruption, notwithstanding that unwanted discharge of pressurized fluid from the disconnected base unit was usually prevented by disengagement of the locking means.
The present invention overcomes the foregoing problems and provides a remote dispenser having an improved locking means.